The increasing use of start-stop systems in motor vehicles requires an expanded demand on the starting system and thereby also requires a functionality to enhance starter devices used to date. More stringent acoustic requirements are, e.g., to be mentioned in this regard as well as the need for the engine to be able to start again when a starting request of the driver is signaled (“change of mind function”). Especially when the internal combustion engine is coming to a stop, this restarting of the engine is not possible using the classic principle of starters used to date.
The German patent publication DE 101 24 506 A1 relates to a starter for a motor vehicle. The starter comprises a housing, an engaging relay disposed parallel thereto and containing a solenoid switch, and an engagement lever rotatably mounted in a transition area between the hollow housing and the engaging relay for coupling the starter motor to the internal combustion machine. A seal is provided to prevent contaminants and moisture from penetrating into the engaging relay. The seal is formed by a rubber membrane within the transition area between the housing and said engaging relay.
The German patent publication DE 10 2009 026 593.7 relates to a method for mechanically synchronizing two rotating, axially offset spur gears as well as to a machine, in particular an electrical starter device. Said starter device comprises a spur gear, particularly configured as a cranking pinion, which interacts with a driving plate disposed on an axial side of the spur gear. Said axial side faces away from a lifting means of the spur gear, the driving plate being restricted in rotation relative to the spur gear, whereby tooth gaps of the spur gear are closed.
Whereas starter devices in motor vehicles used to date perform approximately 40,000 startups and run through the operating cycles required in doing so, the requirement exists with current start-stop modes (SSM functionality) for the internal combustion machine to be able to be turned off in order to save fuel during extended waiting times, hence, e.g., at closed railway intersections, at lengthy red lights or in traffic jams. This is made increasingly possible in current motor vehicles due to the SSM functionality. This means a considerably increased actuating frequency for the starter devices used to date for starting the internal combustion engine, and therefore said starter devices must be designed such that up to a half million or more startups of the internal combustion engine are ensured. Firstly high demands are thus place on the service life and reliability of said starter devices; and secondly in light of such a high number startups, the demand increases for a minimization of the accompanying noise. It has been established that the starter device represents a considerable source of noise which is no longer tolerated by the passengers and automobile manufacturers of luxury passenger cars, in which said starter devices are used.
Normally the startup of an internal combustion machine is introduced in such a way that the internal combustion machine is turned over such that a compression of a suitable gas-air mixture is thereby generated; thus enabling said machine to run independently after the mixture has been ignited. To meet this end, electrically driven starter devices are normally used, the pinions of which are guided into the starter ring gear of the internal combustion machine and drive said ring gear. In so doing, it is possible that the pinion does not optimally engage in the ring gear. On the contrary, the pinion toothing does not engage in a gap between two teeth of the ring gear but said toothing strikes tooth on tooth and thus prevents engagement. Borderline cases can occur somewhere in between meshing and striking tooth on tooth, where, e.g., the tooth strikes only with half a side on the toothing of the ring gear. The noise emission is considerable when the toothings do not engage with each other properly.
The Japanese patent application JP 04 168 947 relates to a starter device. According to this solution, a component is provided with a solid lubricant to prevent adhesive wear and to dampen noise occurring during metal contact, said solid lubricant being applied to the pinion toothing.